A number of commercially available television sets and video cassette recorders have picture-in-picture (also called "pix-in-pix" or simply P-I-P) and multi-picture (also called "multi-pix") provisions.
In one form of the multiple-picture feature, essentially multiple "still" pictures derived from the same video source (e.g., channel) "taken" at successively different times are simultaneously displayed in a rectangular array and thereafter periodically and sequentially up-dated. This provides a type of static stroboscopic display which, may be used to study the progression of an action such as swinging a golf swing.